The Hopkins 4-pole wiring harness made for your 1996 Nissan Pickup is kit # HM43505 which appears on the linked page along with similar item # C55353 from Curt. All of these wiring kits use custom-fit plugs for simple installation at the truck's taillight connectors. No splicing is required for these custom kits.
The Hopkins hardwired harness # HM48895 is made for newer vehicles that use LED lights. This item has a red wire that splices to a vehicle's brake light wire and these signals... view full answer...
If I am understanding you correctly it sounds like when you test your trailer with a 12 volt power source all of the tail light functions work correctly, but then when you connect the trailer to your tow vehicle is when you see problems.
If this is the case then it sounds like the problem is on the vehicle side of the wiring and the trailer is good. You could further confirm this if you wanted by trying a different tow vehicle to see if the problem persists or goes away.
One thing you... view full answer...
A ground problem is a possibility but having an insufficient ground connection usually causes the trailer lamps to behave erratically, or to work properly until the vehicle headlights are switched on.
The best place to start would be to use a circuit tester like part # PTW2993 and test the trailer connector as each function is tested. This will tell you if the problem exists on the vehicle or the trailer.
If your testing shows that the trailer connector is functioning properly, then... view full answer...
If you have the Hopkins Wiring Harness # HM43505 installed on your 1997 Nissan pickup you will want to check the 4-flat connector with a circuit tester # PTW2993 and make sure that the wiring on the vehicle is correct and that you have a good ground.
It sounds like a ground problem on the trailer is what is causing your lighting problem. You will want to check that the white ground wire on the trailers 4-way is properly grounded to a good, clean area of bare metal on the frame.
You will... view full answer...
Go To Results